EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Robust Late 21st Century Shift in the Regional Monsoons in RegCM-CORDEX Simulations

Moetasim Ashfaq1, Tereza Cavazos2, Michelle Reboita3, José Abraham Torres-Alavez4, Eun-Soon Im5, Christiana Olusegun6, Lincoln Alves7, Kesondra Key1, Mojisola Adeniyi8, Moustapha Tall9, Mouhamadou Bamba Sylla10, Shahid Mehmood1,11, Qudsia Zafar12, Sushant Das4, Ismaila Diallo13, and Erika Coppola4
Moetasim Ashfaq et al.
  • 1Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America (
  • 2Center for Scientific Research and Higher Education of Ensenada, Baja California, Mexico
  • 3Federal University of Itajubá, Itajubá, MG, Brazil
  • 4Abdus Salam International Centre for Theoretical Physics, Trieste, Italy
  • 5Department of Civil and Environmental Engineering/ Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong
  • 6Centre for Atmospheric Research, National Space Research and Development Agency, Anyigba, Nigeria
  • 7National Institute for Space Research, Earth System Science Center, São José dos Campos, São Paulo, Brazil
  • 8Department of Physics, University of Ibadan, Ibadan, Nigeria
  • 9Laboratoire de Physique de l’Atmosphère et de l’Océan-Siméon Fongang, Ecole Supérieure Polytechnique, Université Cheikh Anta Diop, PO Box: 5085, Dakar-Fann, Dakar, Senegal
  • 10African Institute for Mathematical Sciences, AIMS Rwanda center, P. O. Box, 7150, Kigali, Rwanda
  • 11Research Center for Environmental Changes, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
  • 12Global Change Impact Studies Centre, Islamabad, Pakistan
  • 13Departement of Geography, University of California - Los Angeles, Los Angeles, CA, USA

We use an unprecedented ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide, for the first time, an RCM-based global view of monsoon changes at various levels of increased greenhouse gas (GHG) forcing. All regional simulations are conducted using RegCM4 at a 25km horizontal grid spacing using lateral and lower boundary forcing from three General Circulation Models (GCMs), which are part of the fifth phase of the Coupled Model Inter-comparison Project (CMIP5). Each simulation covers the period from 1970 through 2100 under two Representative Concentration Pathways (RCP2.6 and RCP8.5). Regional climate simulations exhibit high fidelity in capturing key characteristics of precipitation and atmospheric dynamics across monsoon regions in the historical period. In the future period, regional monsoons exhibit a spatially robust delay in the monsoon onset, an increase in seasonality, and a reduction in the rainy season length at higher levels of radiative forcing. All regions with substantial delays in the monsoon onset exhibit a decrease in pre-monsoon precipitation, indicating a strong connection between pre-monsoon drying and a shift in the monsoon onset. The weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. Monsoon changes under the RCP2.6 scenario are mostly within the baseline variability. 

How to cite: Ashfaq, M., Cavazos, T., Reboita, M., Torres-Alavez, J. A., Im, E.-S., Olusegun, C., Alves, L., Key, K., Adeniyi, M., Tall, M., Sylla, M. B., Mehmood, S., Zafar, Q., Das, S., Diallo, I., and Coppola, E.: Robust Late 21st Century Shift in the Regional Monsoons in RegCM-CORDEX Simulations , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12102,, 2020

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